I wouldn't call it P2W, as you can indeed share DLC with other players by hosting a lobby.
But I will fully agree that every time a new DLC introduces new content, it's blatantly OP.
What then follows is a 3-6 month period before any nerfs are applied (I'm surprised by the current open beta).
And even after all the nerfs have settled, the 50% of the content remains untouched and still too powerful.
I can make a list for every DLC touching on the new content that was OP on release or still is.
Yet for the Free Updates I never have any such complaints, outside of maybe Mystic Culture.
Here are things that are still issues in vanilla multiplayer, as in they are too powerful or cheesy:
- Giant Kings
- Shops
- Landmarks
- Artifacts
- Ancient Wonders (rewards/defenders)
- Ritualist/Warrior
- Tome of Prosperity
- Umbral Abyss
- Tome of the Cleansing Flame
- Corrupted Boon
- Mystic Summoning/Attunement
- Oathsworn Strife/Righteousness
- Infecting / Status Effect Immunity
- Industrious
- Balor/Reaper
- Snow Spirit (the whole Cryomancy tome tbh)
- Damaging World Spells
- Fabled Hunters
- Hermit Kingdom
- Swift Marchers
- Runesmiths
- Cosmoflux Elixir
- Astral Empire Tree
- Knowledge SPIs / Structures
- XP Banner pickups
These are just off the top of my head, there are probably some other, more minor things I forgot.
I can probably make an even longer list of things that are underpowered, which is unfortunate.
Now, a lot (or all) of these things are able to be modded. But it takes tons and tons of hours to do this.
And the more that we change in mods, the more maintenance this requires when the game is updated.
Furthermore, people would prefer to play vanilla if they could. This also creates a divide in the community.